Mindcraft Performance Reports
   

Setting the Record Straight:
Where Salon Got It Right and Wrong

By Bruce Weiner

May 4, 1999

 

In an April 27, 1999 article entitled "Microsoft's Flawed Linux vs. NT Shootout," Salon presented a biased report with innuendos impugning my honesty and Mindcraft's reputation. We want to set the record straight with this rebuttal. Unfortunately, it takes more words to right a wrong than it does to make someone look wrong, so please bear with me.

What's Right

Mr. Leonard had several points right in his article:

 
  • Our tests did find that Windows NT Server is "2.5 times faster than Linux as a file server and 3.7 times faster as a Web server" as he states.

  • Mindcraft did the tests stated in the article under contract with Microsoft and we did them in a Microsoft lab. We couldn't divulge where the tests were being done because we were under a non-disclosure agreement at the time.

    Many have tried to imply that something is wrong with Mindcraft's tests because they were done in a Microsoft lab. You should know that Mindcraft verified the clients were set up as we documented in our report and that Mindcraft, not Microsoft, loaded the server software and tuned it as documented in our report. In essence, we took over the lab we were using and verified it was set up fairly.

  • Mindcraft did conduct a second test with support from Linus Torvalds, Alan Cox, Jeremy Allison, Dean Gaudet, and David Miller. Andrew Tridgell provided only one piece of input before he left on vacation. Mindcraft received excellent support from these leading members of the Linux, Samba, and Apache communities. I thank them for their help and very much appreciate it.

  • The response from the Linux community was more than convulsions. It was net rage.

  • Will did post a request for tuning information. He got one response telling him to use FreeBSD if he wanted a high-speed Web server for static files. Will is not a Mindcraft employee. He is someone who did a posting to a newsgroup about Linux on the system we were going to use for testing. He wanted to remain as anonymous as possible because he didn't want to get a ton of flamming email (based on the email Mindcraft has received, his expectation was underestimated). I see no need to reveal who he is now because his worst nightmare will come true and because he had nothing to do with our test.

 

What's Wrong

Unfortunately, Mr. Leonard did not contact Mindcraft to get information from us. I was at Microsoft conducting the second test of Linux and Windows NT Server myself and was difficult to reach. When I called Mr. Leonard back, he was not in and I left a message. There was no intension to duck his questions as one might infer from his article. The following points will give you the other side of his story.

  • We did not make any posting under false pretences as Mr. Leonard states. Given the anti-Microsoft sentiments in the Linux community, what kind of response do you think we would have received if we said we were benchmarking Linux and Windows NT Server under contract with Microsoft? Take another look at a small part of the net rage e-mail we did receive. A search for Mindcraft at dejanews yielded 764 postings since we published our report. All that doing what Mr. Leonard suggested would have done is to start the net rage and newsgroup postings earlier.

  • For our second test, as Mr. Leonard points out, we sought the tuning suggestions of the people in the Linux community who should really know the answers including Linus Torvalds. But his attribution to Linus that "...but [Mindcraft] isn't giving him the info he needs to do the job right," is wrong.

    All of the Linux experts helping us knew the exact configuration of the system we were testing and knew the benchmarks we were running. The NetBench and WebBench benchmarks are readily available on the Web for free and are probably some of the best documented benchmarks available. We withheld no technical details from him or the other Linux experts.

    Jeremy Allison directly contradicts Mr. Leondard's attribution in a Linux Today article when he says "...I can confirm that we have reproduced Mindcraft's NT server numbers here in our lab." Clearly, Jeremy was tracking what we were doing and we provided him with the information needed to reproduce our tests.

    We exchanged several emails with the Linux experts supporting us and they made suggestions on tunes for Linux, Apache, and Samba. They also provided a kernel patch that was not readily available. We applied all tunes they suggested and the kernel patch. Here are some of the things that happened:

    • Red Hat provided version 1.0 of the MegaRAID driver during our tests and we used it, even though it meant retesting.

    • We sent out our Apache and Samba configuration files for review and received approval of them before we tested. (We actually got better performance in Apache when we made some changes to the approved configuration file on our own).

    • Whenever we got poor performance we sent a description of out how the system was set up and the performance numbers we were measuring. The Linux experts and Red Hat told us what to check out, offered tuning changes, and provided patches to try. We had several rounds of messages between us in which Mindcraft answered the questions they posed.

 
  • We found the Linux experts who supported our second test to be extremely helpful. However, when we saw only one response to Will's posting during the first test, we expected that we would not get much of a response to further queries. I doubt that we would have received much constructive help if we said we were doing a test for Microsoft.

  • Alan Cox is wrong when he says, according to the article, "They [Mindcraft] seem solely intent on trying to re-create their existing pro-Microsoft results and hoping, by attaching some kind of 'Linux top mind' credibility to it, they can do more damage." We're not trying to damage anything. We're reporting the truth of what we find. I asked for Mr. Cox to help provide Linux tuning because Linus Torvalds sent me his name. It was my hope to get Linux performing at an optimal level. I hope that he will participate in the Open Benchmark  Mindcraft has proposed.

The Linux community will gain a real benefit from our benchmark report - a new Linux performance documentation project was created in response to our reporting a lack of such documentation.
 

Attacks on Reputation

Mr. Leonard's attempts to defame Mindcraft's reputation are indicative of a biased and unfounded position. It's not clear if he his trying to gain favor with Linux proponents by his attacks on Mindcraft, if he is simply biased against Microsoft, or if he has something to gain personally by seeing Linux outperform Windows NT Server. I had expected more from a reputable organization like Salon.

  • Putting independent test lab in quotes as Mr. Leonard did in the first paragraph of his article immediately calls into question our independence. That position is most clearly stated in his concluding paragraph on the first page where he states, "... the story underlines the essential worthlessness of commercially sponsored comparison tests. The purpose of these tests is to please the customer who commissions them." So he concludes Mindcraft is not independent and our tests are worthless. Then as a final smear Mr. Leonard quotes an unnamed "engineer familiar with the testing business" in the second to last paragraph on page two to bolster his unfounded views.

    It's clear Mr. Leonard did not do his homework. He obviously knows nothing about the real business of testing and knows nothing about Mindcraft. I have included some background on Mindcraft so you and Mr. Leonard can learn the truth about us.

    As for Mr. Leonard's unnamed "engineer familiar with the testing business," he certainly knows nothing about the professional testing business or he just gave Mr. Leonard the quotation he wanted or he just does not exist. Or, maybe he is the kind of engineer who produces "... numbers that are favorable to the customer" so he can get paid off. Such an engineer could not get or keep a job at Mindcraft.

    To believe this possibly non-existent engineer, you would have to think that we are dishonest and idiots and that our clients are stupid. If our clients get trashed over benchmarks we did for them, how long do you think we'd be able to stay in business. Not 14 years, that's for sure.

The Crux of The Matter

The whole controversy over Mindcraft's benchmark report is about three things: we showed that Windows NT Server was faster than Linux on an enterprise-class server, Apache did not outperform IIS, and we didn't get the same performance measurements for Samba that Jeremy Allison got in the PC Week article or in his lab. Let's look at these issues.

Comparing the performance of a resource-constrained desktop PC with an enterprise-class server is like saying a go-kart beat a grand prix race car on a go-kart race course.
  • Smart Reseller reported a head-to-head test of Linux and Windows NT Server in a January 25, 1999 article; they tested performance on a resource-constrained 266 MHz desktop  PC. One cannot reasonably extrapolate the performance of a resource-constrained desktop PC to an unconstrained, enterprise-class server with four 400 MHz Xeon processors.

  • In a February 1, 1999 article, PC Week tested the file server performance of Linux and Samba on an enterprise-class system. They did not compare it to Windows NT Server on the same system. Jeremy Allison helped with these tests comparing the Linux 2.2 kernel with the Linux 2.0 kernel. I'll show you below what he thinks about Windows NT Server on an enterprise-class server.

 
  • If you doubt our published Apache performance, Dean Gaudet, who wrote the Apache Performance Notes and who provided tuning help for our testing, gives some insights in a recent newsgroup posting. In response to a request for tuning Apache for Web benchmarks, Dean wrote:

    "Unless by tuning you mean 'replace apache with something that's actually fast' ;)

    "Really, with the current multiprocess apache I've never really been able to see more than a handful of percentage improvement from all the tweaks. It really is a case of needing a different server architecture to reach the loads folks want to see in benchmarks."

    In other words, Apache cannot achieve the performance that companies want to see in benchmarks. That's probably why none of the Unix benchmarks results reported at SPEC use Apache.

  • Jeremy Allison believes, according to an April 27, 1999 Linux Today article, that if we do another benchmark with his help, "...this doesn't mean Linux will neccessarily [sic] win, (it doesn't when serving Win95 clients here in my lab, although it does when serving NT clients)..." In other words, in a fair test we should find Windows NT Server outperforming Linux and Samba on the same system. That's what we found.

 
  • Jeremy's statement in the Linux Today article that "It is a shame that they [Mindcraft] cannot reproduce the PC Week Linux numbers ..." shows a lack of understanding of the NetBench benchmark. If he looked at the NetBench documentation , he would find a very significant reason why Mindcraft's measured Samba performance was lower:

    We used 133 MHz Pentium clients while Jeremy and PC Week used faster clients, although we don't know how much faster because neither documented that. We believe that PC Week uses faster clients. Because they use clients that are faster and because so much of the NetBench measurements are affected by the clients, this can account for most of the difference in the reported measurements.

"You can only compare results if you used the same testbed each time you ran that test suite." Understanding and Using NetBench 5.01
 

    In addition, the following testbed and server differences add to the measured performance variances:

    1. Mindcraft used a server with 400 MHz Xeon processors while PC Week used one with 450 MHz Xeon processors. Jeremy did not disclose what speed processor he was using.

    2. Mindcraft used a server with a MegaRAID controller with a beta driver (which was the latest version available at the time of the test) for our first test while the PC Week server used an eXtremeRAID controller with a fully released driver. The MegaRAID driver was single threaded while the eXtremeRAID driver was multi-threaded.

    3. Mindcraft used Windows 9x clients while Jeremy and PC Week used Windows NT clients. According to Jeremy, he gets faster performance with Windows NT clients than with Windows 9x clients.

    Given these differences in the testbeds and servers, is it any wonder we got lower performance than Jeremy and PC Week did?

    If you scale up our numbers to account for their speed advantage, we get essentially the same results.

  • The only reason to use Windows NT clients is to give Linux and Samba an advantage, if you believe Jeremy's claim. In the real world, there are many more Windows 9x clients connected to file servers than Windows NT clients. So benchmarks that use Windows NT clients are unrealistic and should be viewed as benchmark-special configurations.

  • The fact that Jeremy did not publish the details of the testbed he used and the tunes he applied to Linux and Samba is a violation of the NetBench license. If he had published the tunes he used, we would have tried them. What's the big secret?

  • Jeremy states in the article "The essense of scientific testing is *repeatability* of the experiment..." I concur with his assertion. But a scientific test would use the same test apparatus set up and would use the same initial conditions. Jeremy's unscientific test did not use the same testbed or even one with client computers of the same speed we used. We reported enough information in our report so that someone could do a scientific test to determine the accuracy of our findings. Jeremy did not.

    Given the warning in the NetBench documentation against comparing results from different testbeds, it is Jeremy and Linus that are being unscientific in their thrashing of Mindcraft's results. Mindcraft never compared its NetBench results to those produced on a different testbed.

Some Background on Mindcraft

Mindcraft has been in business for over 14 years doing various kinds of testing. For example, from May 1, 1991 through September 30, 1998 Mindcraft was accredited as a POSIX Testing Laboratory by the National Voluntary Laboratory Program (NVLAP), part of the National Institute of Standards and Technology (NIST ). During that time, Mindcraft did more POSIX FIPS certifications than all other POSIX labs combined. All of those tests were paid for by the client seeking certification. NIST saw no conflict of interest in our being paid by the company seeking certification and NIST reviewed and validated each test result we submitted. We apply the same honesty to our performance testing that we do for our conformance testing. To do otherwise would be foolish and would put us out of business quickly.

Some may ask why we decided not to renew our NVLAP accreditation. The reason is simple, NIST stopped its POSIX FIPS certification program on December 31, 1997. That program was picked up by the IEEE and on November 7, 1997 the IEEE announced that they recognized Mindcraft as an Accredited POSIX Testing Laboratory. We still are IEEE accredited and are still certifying systems for POSIX FIPS conformance.

We've received many emails and there have been many postings in newsgroups accusing us of lying in our report about Linux and Windows NT Server because Microsoft paid for the tests. Nothing could be further from the truth. No Mindcraft client, including Microsoft, has ever asked us to deliver a report that lied or misrepresented the results of a test. On the contrary, all of our clients ask us to get the best performance for their product and for their competitor's products. They want to know where they really stand. If a client ever asked us to rig a test, to lie about test results, or to misrepresent test results, we would decline to do the work.

A few of the emails we've received asked us why the company that sponsored a comparative benchmark always came out on top. The answer is simple. When that was not the case our client exercised a clause in the contract that allowed them to refuse us the right to publish the results. We've had several such cases.

Mindcraft works much like a CPA hired by a company to audit its books. We give an independent, impartial assessment based on our testing. Like a CPA we're paid by our client. NVLAP approved test labs that measure everything from asbestos to the accuracy of scales are paid by their clients. It is a common practice for test labs to be paid by their clients.

What's Fair

Considering the defamatory innuendos and bias in the Salon article written by Mr. Leonard, we believe that Salon should take the following actions in fairness to Mindcraft and its readers:

  1. Remove the article from its Web site and put an apology in its place. If you do not do that, at least provide a link to this rebuttal at the top of the article so that your readers can get both sides of the story.

  2. Provide fair coverage from an unbiased reporter of Mindcraft's Open Benchmark  of Windows NT Server and Linux. For this benchmark, we have invited Linus Torvalds, Jeremy Allison, Red Hat, and all of the other Linux experts we were in contact with to tune Linux, Apache, and Samba and to witness all tests. We have also invited Microsoft to tune Windows NT and to witness the tests. Mindcraft will participate in this benchmark at its own expense.

References to NetBench Documentation

The NetBench document entitled Understanding and Using NetBench 5.01 states on page 24, " You can only compare results if you used the same testbed each time you ran that test suite [emphasis added]."

Understanding and Using NetBench 5.01 clearly gives another reason why the performance measurements Mindcraft reported are so different than the ones Jeremy and PC Week found. Look what's stated on page 236, "Client-side caching occurs when the client is able to place some or all of the test workspace into its local RAM, which it then uses as a file cache. When the client caches these test files, the client can satisfy locally requests that normally require a network access. Because a client's RAM can handle a request many times faster than it takes that same request to traverse the LAN, the client's throughput scores show a definite rise over scores when no client-side caching occurs. In fact, the client's throughput numbers with client-side caching can increase to levels that are two to three times faster than is possible given the physical speed of the particular network [emphasis added]."

 

             

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